First-look review: Mavic launches new Cosmic Pro Carbon SL-C and Ksyrium Pro Carbon SL-C wheelsets
Last year Mavic celebrated its 125th year in the cycling industry, and this year the yellow cars of Mavic will perform their 40th year of neutral service for teams at the Tour de France. The company was one of the first to introduce factory-built wheelsets but it has been very slow to develop an all-carbon rim, citing concerns over safety. That is set to change, however, as the company unveiled two new wheelsets at a recent press launch in the French Riviera that feature all-carbon rims. Dave Everett was there for CyclingTips.
Mavic is well known as one of the leading wheel-builders in the bicycle industry. Hailing from Annecy, in the heart of the French Alps, the company played a leading role in ushering the huge shift from hand-built to factory-built wheelsets. Their first successful wheelset of this nature was the original Cosmics, which set the standard for factory-built wheels back in 1994.
In the years since, Mavic has managed to uphold its reputation for high quality aluminium wheels but the brand has lost some of its prestige as it trailed behind other brands that were successfully developing all carbon clincher rims. Mavic is now hoping to regain some of that lost ground with two new wheelsets — the Cosmic Pro Carbon SL-C and Ksyrium Pro Carbon SL-C — which feature all-carbon clincher rims. After spending three days riding the new wheels, I believe Mavic has a great product that stands out from the swathes of carbon wheelsets that already fill bike shops across the globe.
In the past, Mavic’s carbon clinchers were built upon an alloy rim bed because the company felt that full carbon couldn’t offer the same kind of performance and safety that they wanted for their high-end products. While it is easy to criticise this thinking as outdated, talk to any engineer in the industry and they’ll agree — carbon can be manipulated and adjusted to produce a wide variety of characteristics and functions, but it still lags in several key areas when compared to aluminium alloys.
Wheel rims need to cope with stresses arising from multiple directions, both internally and externally, so finding a carbon layup than can handle these loads while still keeping weight to a minimum is no small challenge. Then there are issues with maintaining rim uniformity and satisfying industry standards, which is why Mavic has preferred alloy rim beds for its top-end carbon wheels. Until now.
With the new Cosmic Carbon Pro SL-C and the Ksyrium Pro Carbon SL-C, Mavic now feels it has found a manufacturing process that meets its safety standards. By using multiple layers of seamless one-piece carbon fibre for the rim bed, Mavic can produce a rim contour that meets ISO and ETRTO [European Tyre and Rim Technical Organisation] safety standards straight out of the mould without any need to cut or machine the fibres (which could weaken the structure of the rim).
Creating the new rims has allowed Mavic to move to a wider profile with a 17mm bed for both wheelsets. The Cosmic Carbon Pro SL-C rim is 40mm tall compared to 25mm for the Ksyrium Pro Carbon SL-C, and according to Mavic, the new Cosmic rim weighs 450g compared to 400g for the Ksyrium rim. Interestingly, after so many years of adhering to a sharp V-profile for Cosmic rims, Mavic has moved to a rounder shape for the new all-carbon version.
Mavic will be releasing two versions of each wheelset, one to suit rim brakes, and one for disc brakes. The former will incorporate Mavic’s updated iTgMax technology, a proprietary heat-treatment protocol that increases the Tg (melting temperature of the resin) for superior heat resistance of the brake track. The claimed result from this treatment is that the resin should be able to withstand more than 200°C, which is well in excess of typical braking temperatures.
A new patented laser-treatment process is used to improve the performance of the rim brake track. Mavic uses a laser to burn off the top layer of resin without damaging the carbon fibres below to leave a surface that offers extra grip for the brake pads.
The Cosmic Carbon Pro SL-C uses new elliptical alloy spokes that promises to improve the aerodynamic performance of the wheelset. According to Mavic’s wind tunnel tests, the combination of the new spokes with the 40mm Cosmic rim was faster than some deeper rims with standard spokes.
Mavic continues to make use of aluminium for its hubs along with straight-pull spokes. The company has added a new freehub body design referred to as Instant Drive 360 that utilises a dual-ratchet mechanism. The drive rings have 40 teeth and provide 9° engagement while satisfying Mavic’s goal of keeping the hub weight as low as possible.
The hubsets are built around hollow axles that can be married with different end-caps for compatibility with different axle systems (standard quick release versus thru-axles), which is most relevant important for the disc-equipped versions of each wheelset. As with all of Mavic’s other wheelsets, there will be a choice of freehub bodies to suit Shimano/SRAM and Campagnolo cassettes, while the disc-equipped wheelsets are compatible with center-lock rotors.
Weight, pricing and availability
Mavic reports that the Cosmic Carbon Pro SL-C wheelset weighs 1,450g compared to 1,390g for the Ksyrium Pro Carbon SL-C. As such, neither wheelset will be the lightest in its class, but nevertheless, they are competitive.
The Cosmics and Ksyriums are set to retail in the US for US$2,200 for both rim- and disc-brake versions. UK buyers can expect to pay £1,450 for rim-brake Cosmics while the disc-brake version will cost £50 more. The Ksyriums will retail for £1,500 and £1,575, for the standard and disc versions, respectively. Pricing for other markets (including Australia) is yet to be determined.
Release dates for both wheelsets are just around the corner. The Cosmic Pro Carbon SL-C wheelset for rim brakes will hit dealers in the US, UK and France on March 15, while the disc-brake version will arrive April 15. All other territories will have these wheels on May 1. As for the Ksyrium Pro Carbon SL-C, the rim- and disc-brake versions are set for worldwide release on June 1.
Mavic will be operating its new “Riding is believing” demo program from April 15 in the UK and France, and from May 1 for the rest of the world, through which retailers will have demo wheelsets on hand for free, no-obligation test rides.
The roads of the French Riviera were chosen by Mavic as the testing ground for the new wheels. The rolling coastline from Nice towards the Italian border was the ideal setting for putting the Cosmic Carbon Pro SL-C wheels through their paces. Once the road turned upwards, the famous yellow Skoda cars of Mavic’s neutral service arrived so that the Ksyrium Pro Carbon SL-C wheels could be fitted for the ascents.
My initial reactions for the Cosmic wheels were as you’d expect from a high-end deep section wheel: stiff and lively with fast acceleration due to the low rim weight. The wheels were shod with Mavic’s latest incarnation of their Yksion Pro GripLink (front) and PowerLink (rear) tyres, which I’ve never been impressed with. But Mavic is now using a new rubber compound and tread pattern, and I’m pleased to say has drastically improved the characteristics of the tyres. The wider rim, allowing for a much more supple rounded tyre will also be a factor in this.
Mavic seem to be following the lead of Moto GP tyres because the front tyre now uses a reversed tread pattern. On first inspection, it looks as though the tyre is on backwards but the new pattern works well and grip was never a problem on the roads we rode.
Once I was comfortable with the performance of the tyres, I started paying attention to braking capabilities of the new wheels, and that was when the Mavic’s latest technology started to really stand out.
The famous Col de la Madone served as our first downhill test. The higher slopes have steep, twisting sections that demand quick braking regularly. The lower slopes flow with greater speed, requiring the brakes to be dragged for longer, resulting in the higher temperatures that often cause carbon wheels to suffer.
No matter what sort of braking I undertook, the Ksyriums responded as you’d want them too. At no point did I experience any loss of control, and indeed, the new Ksyriums were virtually as predictable and surefooted as a high-end alloy set (such as Fulcrum’s Racing Zero or Mavic’s own alloy Ksyriums). In addition, there was never any of the shuddering I’ve experienced in the past that comes from poorly aligned braking surfaces.
In this day and age, where it seems relatively easy to produce a lightweight, fast-rolling and aerodynamic wheel, it’s easy to overlook the importance of braking. The extra confidence that comes from knowing you have full control over the wheels when braking actually makes them feel a little faster. Unfortunately, with dry, sunny weather on offer for the duration of the event, I can’t comment on how the wheels will perform in the wet, but I’m very interested in giving them a try on some wet descents.
The wheels come complete with yellow Swissstop pads. Using different pads isn’t recommended by Mavic, though they admit they have found through extensive testing other pads that work better in multiple conditions, though they also found that they were too aggressive reducing the life of the laser etched braking surface. The pads along with the factory fresh braking surface took roughly 50km of rolling hills to bed in until you had a consistent braking performance.
I should touch upon the climbing ability of the Ksyrium wheels too. Over three days, I managed to get in more than 3,000 meters of climbing, and while they may not be the lightest wheelset on the market, they certainly held their own. The wheels climbed rapidly and held their speed well, never feeling sluggish on the steep climbs around Nice. Stiffness was never an issue either, with all power seemingly delivered to where you wanted it at all times.
Finally, the Instant Drive 360 freehub engaged quickly without fault and I’ve always loved the look and enjoyed the performance of Mavic’s skewers.
It seems as if every new wheelset released these days is accompanied by a pile of wind tunnel data and yaw angle numbers in support of the manufacturer’s claims. In this regard, I think it’s refreshing that the people at Mavic don’t seem to be interested in driving their marketing with data, preferring instead to let the wheels to speak for themselves.
Sure, the new Cosmics and Ksyriums are a premium product with a premium price, and sure they roll fast and seem just as stiff as any other wheelset, but where I felt these wheels really shine is their braking performance.
The folks at Mavic have taken their time developing their first full-carbon clincher rims, and while they have been criticised for dragging their heels, the new Cosmics and Ksyriums seem to have benefited enormously. The simple fact that knowing how a wheel will react under braking, no matter how heavy handed you are with it, instills a level of confidence in the product that I haven’t experienced very often.
It’s going to be interesting to see if both wheelsets live up to such strong first impressions when we get some for a long-term test.
Mavic Cosmic and Ksyrium Pro Carbon SL-C wheelset gallery